By connecting internet home appliances to the Internet, interconnection among the home appliances, the Internet, and users is achieved. Generally, the home appliances may be connected to the Internet in a wire or wireless connection mode. The wireless connection mode is widely used because it avoids the complications of cables.
Since signals of the antenna are blocked by metal, a wireless communication module cannot be installed in a chamber enclosed by a metal housing. On the other hand, it is desirable to install the wireless communication module in any position of the home where the appliance as required. Generally, there are three ways to install the wireless communication module.
The antenna and the wireless communication module are made in the same printed circuit board (PCB) and installed in the home appliance. A portion of the housing of the home appliance near the wireless communication module is removed. Taking into account the robustness of the overall structure of the home appliance, it is impossible to remove too much metal. Thereby, the signal of antenna will become poor.
The wireless communication module is installed in the home appliance and the antenna is installed on the outer wall of the housing (or on the inner wall of the housing, in this case, it is also necessary to remove a portion of the housing). The antenna is connected to the wireless communication module by a radio-frequency cable. Obviously, using radio-frequency cable will increase the cost and the wireless signal loss.
The wireless communication module and the antenna are integrated into a single piece, installed on the outer wall of the housing of the home appliance, and connected to a main circuit board in the home appliance by a connector and cables. Way (3) has advantages of convenient installation, convenient updating, and excellent signals without being blocked. Hereinafter, the antenna in the wireless communication module installed in way (3) will be described.
There are many kinds and brands of home appliances, and these kinds and brands of home appliances have different sizes and shapes. Thereby, these wireless communication modules may be required to be installed on different positions on these home appliances, and the design of the antenna is very challenging.
For example, in prior art, there is solution to use inverted F antenna, planar inverted F antenna, monopole antenna and dipole antenna, widely used in mobile terminal equipment, for example, mobile telephone, as the antenna used in the internet home appliance. But these antennas each is a non-balanced antenna, therefore, a current is produced in the metal near the antenna in work, and its performance is affected by the metal housing of the home appliance. Even installed in the central or the corner of the home appliance, the performance of the antenna also varies greatly.